1. Field of the Invention
The present invention relates to a storage system, and particularly relates to volume relocation technology and replication technology.
2. Description of Related Art
Data handled by storage systems managed by business organizations, local authorities, public offices, financial institutions etc. increases year by year on the one hand, while new storage apparatus are added to or exchanged with existing storage apparatus in accompaniment with increase in the amount of data. When a plurality of storage apparatus are added to a storage system in accompaniment with an increase in the amount of data to be managed, configuration of the storage system becomes complex. Virtualization of a storage system is well-known as technology for resolving this kind of problem. Virtualization of the storage system is technology where a plurality of storage apparatus mutually connected to a network are virtualized logically as a single storage system. By virtualizing the storage system, operations management can also be handled jointly as one, and this may contribute towards a reduction in management costs.
By applying storage system virtualization technology, it is possible to classify volumes of a storage system into a plurality of storage tiers taking characteristics such as performance and type etc. as conditions. In Japanese Patent Laid-open Publication No. 2001-47187 and Japanese Patent Laid-open Publication No. 2003-140836, technology is disclosed for arranging this data into optimum storage tiers based on type and data and time of creation etc. of data stored in each volume. For example, in Japanese Patent Laid-open Publication No. 2001-67187, technology is disclosed where data stored in one volume is copied to another volume based on performance information and utilization information for each volume, with the data then being re-arranged.